Loans - Summary of Troubled Debt Restructurings by Loan Class, Excluding Purchased Non-Covered and Covered Loans, Classified Separately Under Restructured Term (Detail) (Excluding Purchased Non-Covered and Covered Loans [Member], USD $) In Thousands, unless otherwise specified	Jun. 30, 2014 Contract	Dec. 31, 2013 Contract	Jun. 30, 2013 Contract
Loans Currently Paying Under Restructured Terms [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	83	67	62
Troubled debt restructuring loans	$ 16,883	$ 15,596	$ 18,335
Loans Currently Paying Under Restructured Terms [Member] | Commercial, Financial and Agricultural [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	5	4	7
Troubled debt restructuring loans	272	515	1,059
Loans Currently Paying Under Restructured Terms [Member] | Real Estate - Construction and Development [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	10	8	7
Troubled debt restructuring loans	2,042	1,896	1,946
Loans Currently Paying Under Restructured Terms [Member] | Real Estate - Commercial and Farmland [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	20	16	16
Troubled debt restructuring loans	7,895	6,396	7,529
Loans Currently Paying Under Restructured Terms [Member] | Real Estate - Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	34	32	31
Troubled debt restructuring loans	6,582	6,699	7,788
Loans Currently Paying Under Restructured Terms [Member] | Consumer Installment Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	14	7	1
Troubled debt restructuring loans	92	90	13
Loans That Have Defaulted Under Restructured Terms [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	25	25	8
Troubled debt restructuring loans	4,197	5,301	2,248
Loans That Have Defaulted Under Restructured Terms [Member] | Commercial, Financial and Agricultural [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	1	3
Troubled debt restructuring loans	449	525
Loans That Have Defaulted Under Restructured Terms [Member] | Real Estate - Construction and Development [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	4	2	1
Troubled debt restructuring loans	69	32	29
Loans That Have Defaulted Under Restructured Terms [Member] | Real Estate - Commercial and Farmland [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	3	5	2
Troubled debt restructuring loans	1,846	2,789	1,493
Loans That Have Defaulted Under Restructured Terms [Member] | Real Estate - Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	12	13	5
Troubled debt restructuring loans	1,798	1,953	726
Loans That Have Defaulted Under Restructured Terms [Member] | Consumer Installment Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	5	2
Troubled debt restructuring loans	$ 35	$ 2